A laboratory reference vaccine to titrate immunogenic activity of antibrucella vaccines in mice

The number of bacteria (CFU) in spleens of mice fifteen days after a standard intraperitoneal challenge of Brucella abortus, is dependent on vaccinal immune status of mice. From this observation, a control method of vaccinal activity was previously proposed, which classified the responses in relation to fixed reference values. A reference vaccine, a lyophilized formalin-killed bacterial cell suspension of B. melitensis strains H38 was prepared and titrated. From the dose response curve, the quantities giving reference values were calculated and expressed in a Unit system. This vaccine makes possible inter-laboratory comparisons of vaccinal activity, that can be expressed on the Units basis.